EHNA hydrochloride. A cGMP-specific phosphodiesterase (PDE2) inhibitor, Synonyms:-erythro-9-(2-Hydroxy-3-nonyl)adenine; (+R,GBS)-Grel-G6-Gamino-GB-Ghexyl-+-methyl-9H-purine-9-ethanol, monohydrochloride; NSC 263164, CAS Number:-58337-38-5, Molecular Formula:-C1GH2GNGO G HCl, 25mg.